Are you using any sounds? Have you placed the sounds in the correct directory or directed the sounds to the correct path? Also you should post your compile log and tell us how you're running it, on a dedicated server or by starting up the game?

What was the path that you put in the ambient_generic? Cause if you read here: http://twhl.info/tutorial.php?id=99 , you need to put the path name as specified. Also if you want rain, you could use env_weather, or something